On the origin of the cholestenoic acids in human circulation.

3β-Hydroxy-5-cholestenoic acid, 3β,7α-dihydroxy-5-cholestenoic acid, and 7α-hydroxy-3-oxo-4-cholestenoic acid are metabolites of cholesterol present at significant concentrations (40–80ng/ml) in human circulation. The 7α-hydroxylated acids may be formed from cholesterol via two major pathways initiated by oxidations at either the 7α- or 27-positions.